In situ autologous growth of self-supporting NiFe-based nanosheets on nickel foam as an efficient electrocatalyst for the oxygen evolution reaction.

A highly efficient and low-cost oxygen evolution reaction electrocatalyst is essential for water splitting. Herein, a simple and cost-effective autologous growth method is developed to prepare NiFe-based integrated electrodes for water oxidation. In this method, a Ni(OH) 2 nanosheet film is first developed on nickel foam by oxidative deposition in a chemical bath solution. The as-prepared nanosheet electrode is then immersed into a solution containing Fe(iii) cations to form an Fe-doped Ni(OH) 2 electrode by utilization of the different solubility of metal cations. Benefiting from its unique and integrated nanostructure, this hierarchically structured electrode displays extremely high catalytic activity toward water oxidation. In 1 M KOH, the electrode can deliver a current density of 1000 mA cm -2 at an overpotential of only 330 mV. This work provides a facile way to produce an efficient, durable, and Earth-abundant OER electrocatalyst with no energy input, which is attractive for large-scale water splitting.